problem with deleting and creating same look up field in a picture library

in my project, there is a picture library with a look field. I delete and create this lookup field like that :

function MajBibliPhotoGare()
{
    var clientContext =SP.ClientContext.get_current();
    var field = clientContext.get_web().get_lists().getByTitle('BibliPhotoGare').get_fields().getByInternalNameOrTitle('IDListeGare');
    clientContext.load(field);
    clientContext.executeQueryAsync(
    Function.createDelegate(this,function() 
        {
            // effacer IDListeGare
            field.deleteObject();
            clientContext.get_web().update();
            clientContext.executeQueryAsync(
            Function.createDelegate(this,function()
                {   
                    // Create lookup Field IDListeGare
                    var oList = clientContext.get_web().get_lists().getByTitle('BibliPhotoGare');
                    var fieldColl = oList.get_fields();   
                    var fieldSchema='';
                    //Add Look up field to the Field Collection  
                    var lookupField = fieldColl.addFieldAsXml(fieldSchema, true, SP.AddFieldOptions.addToDefaultContentType) ; 
                    fieldColl.addFieldAsXml(fieldSchema, true, SP.AddFieldOptions.addToDefaultContentType) ;   
                    lookupField.update(); 
                    clientContext.executeQueryAsync(
                        // Field OK
                        Function.createDelegate(this,function()
                            {
                                // Field OK
                                alert('ok');
                            }), 
                        Function.createDelegate(this, function()
                            {
                                // Field not OK
                                alert(' Not ok');
                            })
                        );
                }),
                Function.createDelegate(this, function()
                    {
                        // error deleting lookup field
                        alert('error deleting lookup field IDListeGare')
                    })
            );
        }),
        Function.createDelegate(this,function()
            {
                // error loading lookup field
                alert('error loading lookup field IDListeGare')
            })
    );      
}

The code is running well, and when i look at the picture library, there is two lookup field named IDListeGare BibliPhotoGare picture Library result

Thank you fo your help.